Recent HIV or STI clusters in youth are associated with a particular social context for sexual behavior. The contexts for adolescent sexual behaviors are understudied. Preliminary work in the high HIV/STI prevalence Lower East Side of New York City indicates that approximately one-third of sexually active youth, age 11-16, have had a sexual experience in a setting where multiple partnerships, partner age disparities and concurrent drug/alcohol use are common; one in eight sampled 11-16 year old youth report attending such a setting. We propose a two-phase qualitative/quantitative quasi- longitudinal study of sexual socialization of LES 13-22 year olds. The project aims to describe for male and female youth 1) the perceived sexual/relational norms and perceived availability of social contexts for sexual/relational interaction; 2) the social controls and pressures facilitating or inhibiting entry into and operating within social contexts; 3) the relationship of norms and pressures to reported incidents of HIV/STI/unintended pregnancy risk; 4) develop descriptions of high- and low-risk relationship/setting trajectories using youth's descriptions of social labeling and other consequences of setting participation, and youth's descriptions of status and relationship management strategies attendant on labeling and other consequences; and 5) refine provisional theory to inform future research and prevention interventions. Developmentally- informed social context and influence theories underlie our provisional model. Eighty 13-22 year old African-American and Latino/a youth will be theoretically sampled to provide understanding of social contexts (e.g., particular high-risk setting participation, no participation). They will take part in three in-depth interviews for the study's qualitative model-building Phase 1. In Phase 2, a refined model will be tested using a variety of multivariate techniques and an additional 320 youth. For those youth that report on the same settings, network analysis can be done of settings. Given the sensitive nature of the research, we will be guided in study protocols by a panel with expertise in research and service to adolescents, including intervention researchers, epidemiologists, clinicians, policy analysts, legal advisors, and parents. Dissemination of results will alert other investigators and interventionists to risks associated with participation in particular social contexts among this age group, and sensitize those who work with adolescents to the influences that adolescents encounter within social contexts.